In order to use a UAV as an aerial wireless base station, the authors in [1]} presented an Air-to-Ground path loss model that helped the academic researchers to formulate many important problems. The authors of [2]}, [3]}, [4]}, [5]}, [6]} utilized this model to study the problem of UAV placement, where the objective is to minimize the number of UAVs for covering a given area.
The authors of [2]} described the tradeoff in this model. At a low altitude, the path loss between the UAV and the ground user decreases, while the probability of line of sight links also decreases. On the other hand, at a high altitude line of sight connections exist with a high probability, while the path loss increases.
However, it is assumed that all users are outdoor and the location of each user can be represented by an outdoor 2D point. These assumptions limit the applicability of this model when one needs to consider indoor users.
